JP2008543584A - Steel materials for the manufacture of endodontic appliances and methods for the manufacture of said appliances - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the manufacturing speed of a blade that can be used in the field of endodontic treatment.
A cylindrical part (1) and a conical part (2) intended to be machined, the machined conical part (2) being a working part of the final therapeutic device. Forming (3), the conical portion (2) becomes the final shape envelope (8) applied to the endodontic instrument after machining. The present invention also relates to a method of manufacturing an endodontic instrument comprising a helical cutting blade utilizing a steel material as described above.

Description

  The present invention relates to the field of endodontic appliances, and more particularly to a conical steel material and a method of manufacturing a cut blade for an alveolar canal appliance.

  This type of endodontic instrument generally consists of a blade and a handle, the blade is inserted into the pulp cavity to be treated and is highly flexible to follow the path of the alveolar tube at the root and during work It must have great mechanical strength so that it does not break accidentally.

  The blade has a generally conical shape in the moving part, but was initially made of steel. As a result of utilization, it has been found that steel does not have sufficient flexibility and strength to withstand the stresses imposed, especially because of the small diameter of the blade.

  Since the publication of Wallia et al. In Journal of Endontic, July 1988, Vol. 14, Issue 7, pp. 346-351, endodontic appliances have been made of nickel titanium alloys, especially 0.020 inches in diameter, i.e. approximately 0.508 mm. Although it is known that it can be made with K-files made from nickel titanium wire, the method starts directly from steel cut from the wire.

  This very tough nickel-titanium alloy responds well to the stresses used, but the problem of machining speed of blades cut by traditional grinding techniques utilizing cylindrical steel, and therefore of manufacturing costs Pose.

  These instruments, for example files called headstrom molds, have been produced long ago by machining, in particular by grinding starting from cylindrical steel, which is carried in front of the wheel and The shape of the cutting blade machining, that is, the incision or groove machining that creates the cutting blade, moves forward of the steel in front of the grindstone and rotates the steel around the steel axis. It is a shape that realizes a taper thanks to the combined movement with.

  Such a device is described in the standard ISO 3630.

  Processes for the manufacture of cut blades that exhibit one or more cutting blades are known, inter alia, from the patents of US Pat. No. 5,527,205, US Pat. No. 5,628,674, and US Pat. No. 5,655,950. These patents describe the use of cylindrical steel with an alloy containing at least 40% titanium and approximately 50% nickel and having a diameter of less than 0.07 inches. The blade obtained according to the described method has at least one longitudinal groove that is cut helically with only one movement and passage in front of the wheel. The described method aims to obtain blades that are free of defects and free of metal deformation.

  The documents of US Pat. No. 5,527,205 and US Pat. No. 5,655,950 further clarify that at least 25% of the diameter of the cylinder is removed in the portion corresponding to the most cut area.

  This embodiment of a conical endodontic device from cylindrical steel is described in a paper that Sylvie YGUEL HENRY underwent an open oral examination at Nancy on July 6, 1988, as well as Marie-Christine SPOHR, April 1987. It was known on the filing date of these patents because the embodiment was mentioned in a paper that received a public oral examination in Nancy on 29th. This embodiment has also been taken up by Alain CAVALLI in a paper that was dictated on March 29, 1982 in Marseille.

  The manufacturing method of blades cut from cylindrical steel presents great difficulties in obtaining the overall conical shape of the cut blades, whether steel or nickel-titanium alloys. This taper can vary from one to the other, and in any case, the cut blade exhibits a small cut area, that is, a portion that requires significant removal of material by polishing. In the portion of the blade to be cut that has a larger diameter, and therefore closer to the diameter of the cylindrical steel material, the cutting speed may be faster.

The removal of this material with differences along the part to be cut can lead to various technical problems that affect the long production time of the machined part and thus the high costs for the manufacture of the respective endodontic appliance Pose.
US Pat. No. 5,527,205 US Pat. No. 5,628,674 US Pat. No. 5,655,950

  The present invention improves the production rate of cut blades available in the field of endodontic treatment, and more particularly solves this main problem for obtaining an instrument made of nickel-titanium. With the goal.

  The present invention relates to a steel material that enables the manufacture of endodontic appliances by grinding techniques, said steel material having a generally conical cone intended for the steel part to be machined into a cylindrical part. Characterized in that it has a shaped part, said machined part forming the working part of the final endodontic instrument. The generally conical conical portion is what will be the final shaped envelope that is applied to the endodontic appliance after machining.

  The present invention also relates to a method for manufacturing an endodontic instrument comprising at least one helical cutting blade using steel as described above.

  The use of the steel material according to the invention makes it possible to avoid long machining of the entire extra material, which means that the extra material, i.e., beyond the envelope of the sought endodontic instrument, in particular the instrument It is a material located at the thinnest end portion. At this point, over 60% of the material may sometimes be removed during grinding by conventional methods using cylindrical steel.

  The main advantage of the steel material comprising a generally conical conical part and the method according to the invention is therefore an improvement in the production rate of endodontic appliances, and more particularly a representative example of nickel-titanium It is the manufacture of instruments using alloys that are durable and difficult to machine.

  This speed of manufacture logically appears as a reduction in the cost of manufacturing the instrument.

  Other features and advantages of the present invention will become apparent from the following description, given with reference to the accompanying drawings, given by way of non-limiting example only.

  FIG. 1 is a diagram of conical steel before and after machining, and a schematic view of the cut surface at two points in the generally conical conical portion of these steels.

  FIG. 2 shows a conical steel material with three different tapers before and after machining.

  FIG. 3 shows a steel with variable taper with a concave working part.

  The prior art describes a number of devices that can cut cylindrical steel to form a tool, more specifically to form a blade that can be used in the field of endodontic treatment, The documents of the above-mentioned US Pat. No. 5,527,205, US Pat. No. 5,628,674 and US Pat. No. 5,655,950 describe in particular a fixing device which makes it possible to hold a cylindrical steel material, said steel material. 1 shows a machine with means enabling it to form a helical groove and finally a blade that can be used for endodontic treatment by moving it in front of the wheel by rotation and translation.

According to the present invention, conical steel is intended to be cut using a machine that includes the following main mechanisms:
・ Steel input device that enables supply of parts to be cut to the work area,
· Spindles that accept steel and are intended to hold steel during machining,
・ Machining grindstones intended to cut steel, moving in a vertical direction relative to the spindle axis,
A guidance device, which is positioned almost opposite the grindstone and serves to hold the instrument during machining. The guide device is moved in pairs with the grindstone in relation to the spindle axis.
A power unit that rotates the steel around the axis of the steel and allows the steel to move in the forward direction during cutting.
-Machined parts removal equipment.

  More precisely, the grinding wheel for machining is provided with a rotation axis parallel to the axis of the spindle or a rotation axis included in a vertical plane parallel to the axis of the spindle. The angle in relation to the horizontal position is variable depending on the desired shape.

  According to the invention, and as shown in FIG. 1a, the steel material enabling the manufacture of an endodontic instrument has a cylindrical part 1 and a generally conical conical part 2, which is , Fixed in the spindle, and held for a portion of its length during machining.

  The generally conical conical portion 2 is machined during the forward movement of the grinding wheel. More precisely, this generally conical conical portion becomes the geometric envelope of the final device.

  This final instrument after cutting is shown in FIG. 1b, where the working part 3 of the instrument has a plurality of cutting blades. The working part 3 is the part of the instrument that prepares the alveolar tube during the work of the doctor.

  The steel material shown in FIG. 1a has a generally constant conical conical portion 2, the taper ratio of this generally conical conical portion preferably comprised between 2 and 20%. .

  The generally conical conical portion 2 of the steel material does not exceed the final diameter of the instrument by more than 20%. As such, the material removed during machining is reduced to a maximum.

  The parts removed by machining the steel are illustrated in the cross-sectional views realized according to AA and BB in FIGS. 1a and 1b. The illustration of the cut surface of the final tool shows in this example three cutting edges obtained after three grinding operations and three spiral cuts.

  The steel material is preferably composed of an alloy of titanium and nickel, however, it does not exclude the use of steel or a different alloy.

  The present invention requires very little material to be removed compared to known techniques using cylindrical steel, so that the alloys used to manufacture endodontic appliances are strong and difficult to machine. Show greater benefits.

As shown in FIG. 1b, the final endodontic instrument has a plurality of helical cutting blades, and the method of making this instrument according to the invention consists of:
The provision of a steel material, the steel material being a generally conical conical part intended to be machined and a cylindrical part that allows the steel material to be fixed in a holding spindle Which has
Moving the steel in a forward direction, which moves with a slow rotation in front of the rotating wheel, so as to perform a hollow spiral cutting that produces a helical cutting edge. is there,
-Repeat the previous movement the same number of times as the number of cutting blades the instrument has.

  The method for manufacturing an endodontic instrument according to the present invention uses a steel material, in which an overall conical conical portion is applied to the endodontic instrument after machining so as to have a final shape envelope. The taper ratio of the generally conical conical portion is preferably comprised between 2 and 20%, and the diameter of each cutting surface of the generally conical conical portion is 20 times the final diameter of the instrument. % Or more.

  The manufacturing method of the endodontic appliance preferably uses a steel material made of an alloy of nickel and titanium.

  The method is characterized according to the invention by a steel advance speed of at least 200 mm / min, which can exceed 300 mm / min for the production of endodontic appliances from steel with a taper ratio of 2.

  These forward speed values are much lower at 5 inches / minute or 127 mm / minute as shown in the above-mentioned US Pat. No. 5,527,205, US Pat. No. 5,628,674, and US Pat. No. 5,655,950. It should be compared with the value.

  The forward speed associated with the rotational speed about the axis of the steel material determines the pitch of the spiral to be cut, which can be constant or variable depending on the model of the tool to be manufactured.

  The machining machine utilized in the method can adjust various main speeds, which are the steel advance speed and the steel rotation speed along its axis, as well as the grinding wheel rotation speed. .

  The grindstone can be tilted to achieve various shapes of grooves in the steel. The characteristics of the grindstone that can be used vary depending on the material of the steel material and the type of equipment to be manufactured. For example, a diamond grindstone, a vitrified grindstone, and the like can be utilized.

  In this way, a wide variety of endodontic appliances can be manufactured at a much faster rate than known techniques, due to the various adjustable parameters of the machine.

  According to the invention, differently shaped instruments can be produced, but for example, as shown in FIG. 2, three different tapers 5, 6 and 6 along a generally conical conical portion 2, It is possible to cut the steel material 4 having 7.

  The endodontic instrument obtained after machining according to the method described in the present invention is shown in FIG. 2b. In this figure, representing the original steel envelope 8 around the moving part 3 showed that the material removed by grinding was very small in volume, which allowed very fast machining speeds To do.

  FIG. 3 shows another variant of the steel material that can be used, in particular a sharp, possibly smooth and concave working part 3, for example as shown in FIG. 3 b. It is for obtaining the instrument which has.

  For the production of this type of instrument, the generally conical conical portion of the steel shown in FIG. 3a can be a constant taper or a variable taper, with a recess portion close to that of the final instrument. 9

  In addition to the previously described variants, many steel materials are conceivable, and the length of the cylindrical part and the overall conical part can be varied in relation to each other without departing from the scope of the invention. Various shapes can be envisaged and the method makes it possible to obtain a wide range of endodontic appliances.

  The described method for obtaining an endodontic instrument can be carried out using a variety of machines, in which the steel material is grabbed, the steel material is placed into a spindle and the steel material is machined after machining. The means that make it possible to take out can vary greatly without departing from the scope of the invention.

  The same is true for motors and all environments that allow a machine for machining to be operated in an optimal manner.

  Grinding wheels that allow for the grinding of steel and the production of helical grooves can be rotated at various speeds, for example at a speed of about 5500 revolutions per minute, and are efficient and as fast as possible. As long as it makes it possible to guarantee the forward speed of the steel, it can have various abrasives. This is because this forward speed is generally a factor limiting the production speed of the instrument.

  The rotational speed of the steel itself around its axis can also vary over a fairly wide range depending on the tool being sought, the efficiency of the grinding and the forward speed.

  Depending on the use of this material to produce steel, the manufacturing parameters of the instrument will logically change.

  Once the instrument is obtained, various removal means can be envisaged, connected or not connected to the packaging and packaging line, to maximize automation of mass production.

  Of course, the present invention is not limited to the embodiments described and illustrated by way of example, but also includes all technical equivalents and combinations thereof.

Schematic illustration of conical steel before and after machining, and schematic illustration of the cut surface at two points in the generally conical conical part of these steels Schematic showing a conical steel with three different tapers before and after machining Schematic showing a steel with a variable working part and variable taper

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical part 2 Conical part 3 Operation | movement part 4 Steel material 5 Taper 6 Taper 7 Taper 8 Envelope 9 Recessed part

Claims (9)

A steel that enables the manufacture of endodontic appliances by grinding technology,
Said steel material has a cylindrical part (1) and a generally conical conical part (2) intended to be machined;
The machined part is what forms the working part (3) of the final endodontic instrument;
In the steel material, the generally conical conical part (2) has an endodontic treatment after machining with a grinding wheel with a rotation axis parallel to the axis of the spindle or a rotation axis contained in a plane parallel to the axis of the spindle. A steel material, characterized in that it becomes an envelope (8) of the final shape applied to the instrument.   The steel material of claim 1, wherein the diameter of each cutting surface of the generally conical conical portion does not exceed 20% or more of the diameter of the final device.   Steel according to claim 1 or 2, wherein the taper ratio of the generally conical conical part (2) is comprised between 2 and 20%.   4. Steel according to claim 1, wherein the generally conical conical part (2) has at least two different tapers (5, 6, 7).   Steel material according to any one of claims 1 to 3, wherein the generally conical conical portion (2) has one or more recesses (9).   It is steel materials, Comprising: The steel materials as described in any one of Claims 1-5 manufactured with steel or the alloy of titanium and nickel. A method of manufacturing an endodontic treatment instrument,
The next process,
Supply of steel material, the steel material being a generally conical conical part (2) intended to be machined and a cylindrical part that allows the steel to be fixed in a holding spindle A process comprising (1),
Movement of the steel in the forward direction, the steel moving with a slow rotation in front of the rotating wheel, so as to perform a hollow spiral cutting that produces a helical cutting edge; The grinding wheel has a rotation axis parallel to the spindle axis or a rotation axis included in a plane parallel to the spindle axis.
A method for manufacturing an endodontic instrument comprising at least one helical cutting blade, characterized by a continuous sequence of previous movements, the same number of times as the number of cutting blades the instrument has. A method of manufacturing an endodontic treatment instrument,
The generally conical conical part (2) of the steel material becomes the final shape envelope (8) applied to the endodontic appliance after machining,
The taper ratio of the generally conical conical portion is comprised between 2 and 20%;
8. The method of manufacturing an endodontic device according to claim 7, wherein the diameter of each cutting surface of the generally conical conical portion (2) does not exceed 20% or more of the diameter of the final device. A method for producing an endodontic instrument, wherein the steel is made of an alloy of nickel and titanium,
The method for producing an endodontic treatment device according to claim 8, wherein the advancement speed of the steel material is at least 200 mm / min.

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